Active control of surface drag

ABSTRACT

A system and method is described generally for deforming a surface of a body to alter a fluid flow in order to change the characteristics of the fluid flow about the body.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is related to and claims the benefit of theearliest available effective filing date(s) from the following listedapplication(s) (the “Related Applications”) (e.g., claims earliestavailable priority dates for other than provisional patent applicationsor claims benefits under 35 USC §119(e) for provisional patentapplications, for any and all parent, grandparent, great-grandparent,etc. applications of the Related Application(s)).

1. For purposes of the USPTO extra-statutory requirements, the presentapplication constitutes a continuation in part of currently co-pendingUnited States patent application entitled ACTIVE CONTROL OF A BODY BYALTERING SURFACE DRAG, naming Roderick A. Hyde, Nathan P. Myhrvold,Lowell L. Wood, Jr., Alistair K. Chan, and Clarence T. Tegreene asinventors, U.S. Ser. No. 11/633,083, filed contemporaneously herewith.

2. For purposes of the USPTO extra-statutory requirements, the presentapplication constitutes a continuation in part of currently co-pendingUnited States patent application entitled SYSTEM AND METHOD FORDEFORMING SURFACES, naming Roderick A. Hyde, Nathan P. Myhrvold, LowellL. Wood, Jr., Alistair K. Chan, and Clarence T. Tegreene as inventors,U.S. Ser. No. 11/633,145, filed contemporaneously herewith.

3. For purposes of the USPTO extra-statutory requirements, the presentapplication constitutes a continuation in part of currently co-pendingUnited States patent application entitled SYSTEM AND METHOD FOR CHANGINGTHE CONVECTIVE HEAT TRANSFER OF A SURFACE, naming Roderick A. Hyde,Nathan P. Myhrvold, Lowell L. Wood, Jr., Alistair K. Chan, and ClarenceT. Tegreene as inventors, U.S. Ser. No. 11/633,082, filedcontemporaneously herewith.

BACKGROUND

The description herein generally relates to the field of vehiclesutilizing thrust and/or experiencing drag traveling through anenvironmental media, and more particularly the modification of thrust,turbulence and/or drag. More generally the description relates to theactive deformation of a surface to alter the characteristics of thesurface to flow or surface to surface interface, by creating adynamically changing surface geometry.

SUMMARY

In one aspect, a method includes but is not limited to a method ofaltering fluid flow about a body moving relative to a fluid. The methodcomprises exposing a first surface of the body to the fluid. The firstsurface extends in at least a first direction and a second direction,the first direction is orthogonal to the second direction. The methodalso comprises generating more than one deformation of the first surfaceof the body. The more than one deformation comprises a series ofdeformations moving in the first direction and the second direction.

In another aspect, a method includes but is not limited to a method ofaltering fluid flow about a surface where the surface is defined by afirst direction and a second direction orthogonal to the firstdirection. The method comprises coupling to the surface at least oneactuator capable of deforming the surface. The method also comprisesdetecting at least one physical state based on a signal from at leastone sensor. Further, the method comprises controlling the at least oneactuator based on the signal to create deformations which move with avelocity having components of both the first and second directions,responsive to the detecting of at least one physical state.

In yet another aspect, a method of changing the characteristics of asurface-to-surface contact comprises providing a first surface. Themethod also comprises providing a second surface in at leastintermittent contact with the first surface. Further, the methodcomprises selectively deforming the first surface with one or moreactuators associated with the first surface to produce a surface wave onthe first surface.

In still yet another aspect, a method of controlling fluid-bodyinteraction comprises determining a first set of fluid-body interactioncharacteristics. The method also comprises defining a set of travelingbody parameters along at least two different directions in response todetermining a first set of fluid-body interaction characteristics. Themethod also comprises producing a signal corresponding to the definedset of traveling body parameters.

In addition to the foregoing, other method aspects are described in theclaims, drawings, and text forming a part of the present disclosure.

In one or more various aspects, related systems include but are notlimited to circuitry and/or programming for effecting theherein-referenced method aspects; the circuitry and/or programming canbe virtually any combination of hardware, software, and/or firmwareconfigured to effect the herein-referenced method aspects depending uponthe design choices of the system designer.

In one aspect, a system includes but is not limited to a fluid flowalteration system. The system comprises a body having a first surfaceexposed to the fluid. The first surface extends in at least a firstdirection and a second direction. The first direction is orthogonal tothe second direction and the fluid has generally relative motion withrespect to the first surface. The system also comprises at least onedeformation device. The deformation device selectively causes deformingmovement of the first surface in the first and second direction.

In another aspect, a device for creating a selectively variablefrequency sound includes an airway through which a fluid is directed toflow. The device includes a selectively deformable surface that definesat least a portion of the airway. The device also includes an actuatorsystem configured to produce a surface wave in response to an input, thesurface wave cause a change in the fluid flow and thereby causes achange in the sound frequency generated by the device.

In addition to the foregoing, other system aspects are described in theclaims, drawings, and text forming a part of the present disclosure.

In addition to the foregoing, various other method and/or system and/orprogram product aspects are set forth and described in the teachingssuch as text (e.g., claims and/or detailed description) and/or drawingsof the present disclosure.

The foregoing is a summary and thus contains, by necessity,simplifications, generalizations and omissions of detail; consequently,those skilled in the art will appreciate that the summary isillustrative only and is NOT intended to be in any way limiting. Otheraspects, features, and advantages of the devices and/or processes and/orother subject matter described herein will become apparent in theteachings set forth herein.

BRIEF DESCRIPTION OF THE FIGURES

The foregoing summary is illustrative only and is not intended to be inany way limiting. In addition to the illustrative aspects, embodiments,and features described above, further aspects, embodiments, and featureswill become apparent by reference to the drawings and the followingdetailed description, of which:

FIG. 1 is an exemplary diagram of a velocity profile of fluid flow overa flat plate.

FIG. 2 is an exemplary diagram of a velocity profile of fluid flow overa flat plate in which horizontal velocity has been added within theboundary region.

FIG. 3 is an exemplary diagram of a traveling surface wave on an objectin the presence of a fluid flow.

FIG. 4 is an exemplary diagram of laminar and turbulent flowcharacteristics.

FIG. 5 is an exemplary block diagram of a drag control system using anactive skin.

FIG. 6 is an exemplary block diagram of a traveling surface wave in thepresence of a fluid flow.

FIG. 7A is an exemplary diagram of an active skin surface having an airelement above the skin surface.

FIG. 7B is an exemplary diagram of the active skin surface of FIG. 7Ahaving the air element displaced above the skin surface.

FIG. 8A is an exemplary diagram of an active skin surface having an airelement above the skin surface.

FIG. 8B is an exemplary diagram of the active skin surface of FIG. 8Ahaving the air element displaced above the skin surface.

FIGS. 9A-E are exemplary diagrams of a deformable surface having varioustraveling surface waves.

FIG. 10 is an exemplary embodiment of an exemplary waveform.

FIG. 11 is an exemplary diagram of an exemplary sinusoidal wave.

FIG. 12 is an exemplary diagram of an actuator system for an active skinsystem.

FIG. 13 is an exemplary diagram of an actuator system for an active skinsystem.

FIG. 14 is an exemplary diagram of various velocity profiles in a tubeor channel.

FIG. 15 is an exemplary diagram of an active skin system having flowsensors associated therewith.

FIG. 16 is an exemplary diagram of an active skin system having aferrous layer and a solenoid layer.

FIG. 17 is an exemplary diagram of an active skin system having aflexible layer and a responsive layer.

FIG. 18 is an exemplary process diagram of a surface deformation method.

FIG. 19 is another exemplary process diagram of a surface deformationmethod.

FIG. 20 is an exemplary diagram of a sound generating device having aselectively deformable surface.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings, which form a part hereof. In the drawings,similar symbols typically identify similar components, unless contextdictates otherwise. The illustrative embodiments described in thedetailed description, drawings, and claims are not meant to be limiting.Other embodiments may be utilized, and other changes may be made,without departing from the spirit or scope of the subject matterpresented here. Those having skill in the art will recognize that thestate of the art has progressed to the point where there is littledistinction left between hardware and software implementations ofaspects of systems; the use of hardware or software is generally (butnot always, in that in certain contexts the choice between hardware andsoftware can become significant) a design choice representing cost vs.efficiency tradeoffs. Those having skill in the art will appreciate thatthere are various vehicles by which processes and/or systems and/orother technologies described herein can be effected (e.g., hardware,software, and/or firmware), and that the preferred vehicle will varywith the context in which the processes and/or systems and/or othertechnologies are deployed. For example, if an implementer determinesthat speed and accuracy are paramount, the implementer may opt for amainly hardware and/or firmware vehicle; alternatively, if flexibilityis paramount, the implementer may opt for a mainly softwareimplementation; or, yet again alternatively, the implementer may opt forsome combination of hardware, software, and/or firmware. Hence, thereare several possible vehicles by which the processes and/or devicesand/or other technologies described herein may be effected, none ofwhich is inherently superior to the other in that any vehicle to beutilized is a choice dependent upon the context in which the vehiclewill be deployed and the specific concerns (e.g., speed, flexibility, orpredictability) of the implementer, any of which may vary. Those skilledin the art will recognize that optical aspects of implementations willtypically employ optically-oriented hardware, software, and or firmware.

The foregoing detailed description has set forth various embodiments ofthe devices and/or processes via the use of block diagrams, flowcharts,and/or examples. Insofar as such block diagrams, flowcharts, and/orexamples contain one or more functions and/or operations, it will beunderstood by those within the art that each function and/or operationwithin such block diagrams, flowcharts, or examples can be implemented,individually and/or collectively, by a wide range of hardware, software,firmware, or virtually any combination thereof. In one embodiment,several portions of the subject matter described herein may beimplemented via Application Specific Integrated Circuits (ASICs), FieldProgrammable Gate Arrays (FPGAs), digital signal processors (DSPs), orother integrated formats. However, those skilled in the art willrecognize that some aspects of the embodiments disclosed herein, inwhole or in part, can be equivalently implemented in integratedcircuits, as one or more computer programs running on one or morecomputers (e.g., as one or more programs running on one or more computersystems), as one or more programs running on one or more processors(e.g., as one or more programs running on one or more microprocessors),as firmware, or as virtually any combination thereof, and that designingthe circuitry and/or writing the code for the software and or firmwarewould be well within the skill of one of skill in the art in light ofthis disclosure. In addition, those skilled in the art will appreciatethat the mechanisms of the subject matter described herein are capableof being distributed as a program product in a variety of forms, andthat an illustrative embodiment of the subject matter described hereinapplies regardless of the particular type of signal bearing medium usedto actually carry out the distribution. Examples of a signal bearingmedium include, but are not limited to, the following: a recordable typemedium such as a floppy disk, a hard disk drive, a Compact Disc (CD), aDigital Video Disk (DVD), a digital tape, a computer memory, etc.; and atransmission type medium such as a digital and/or an analogcommunication medium (e.g., a fiber optic cable, a waveguide, a wiredcommunications link, a wireless communication link, etc.).

Air acts as a viscous fluid at sub-sonic speeds, any object movingthrough it collects a group of air particles which it tends to pullsalong with it. Air particles close to the surface of the object tend tomove with approximately the same velocity as the object due to viscousadhesion. As a flat plate, airfoil, or other object moves through a freestream of air at a given relative velocity, viscous adhesion causes avery thin layer of air having relative velocities below that of therelative free stream velocity, to form adjacent the object surface. Thislayer, known as the “boundary layer”, constitutes the interface betweenthe airfoil and its surrounding air mass. Although many of the conceptsdescribed are being described with reference to air as being the fluidmedium, it should be noted that the scope is not so limited and that anyof a variety of fluids may be equally as applicable within the contextof the description and claims.

Referring now to FIG. 1, a fluid flow state 100 over a flat plate 120 isdepicted. Flat plate 120 is provided as an example only, any of avariety of surfaces including curved or discontinuous surfaces may beequally applicable. A “y” coordinate is oriented perpendicular to flatplate 120. In a conventional laminar flow the relative velocity 130 ofthe fluid (e.g. gas, liquid, solid suspension that behaves like aliquid) near flat plate 120, is less than the relative velocity 110 ofthe fluid away from flat plate 120, with the relative velocity 140 atthe surface of flat plate 120 typically having a relative velocity valueof zero. A zero relative velocity refers to no relative velocity withrespect to a reference frame, in this example the surface of the flatplate. The continuum of relative velocities traces a relative velocityprofile 150. The position 160 where the relative velocity approaches thefree stream velocity is typically referred to as the outer limit of theboundary layer. The drag force on the object is related to theintegrated difference between the free stream velocity 110 and therelative velocities in the boundary region defined by velocity profile150 and outer limit of the boundary layer 160. Referring now to FIG. 2,a fluid flow state 200 is depicted, where a horizontal velocity 235 hasbeen added within the boundary region. The integrated difference betweenthe freestream velocity 110 and the relative velocities within boundarylayer 160 is therefore reduced, which has the effect of reducing drag.The increased relative velocity 235 may be induced by providing motionsof the object's surface. Such motions may be in the form of travelingsurface waves, surface displacements, surface deformations, and the like(See FIG. 3). Systems and methods discussed herein may provide suchinduced increases in relative velocity of boundary layer flow to aid inreducing drag. Conversely, by using surface waves, displacements, and/ordeformations to induce decreased relative flow velocities, increases indrag for purposes of braking and/or control may be advantageously andselectively generated.

Another manner in which to alter the drag on an object may be to alterthe onset of turbulent flow around the object. Conceptually, theboundary layer may be simply thought of as the layer of air surroundingan object in which the relative velocity of the layer of moleculesclosest to the object is at or near zero, and in which the relativevelocity at successively distant points from the object increases untilit approaches that of the free stream, at which point the outer limit ofthe boundary layer is reached. Generally, boundary layers may becharacterized as laminar or turbulent, although there is a region oftransition between laminar and turbulent that may, in some cases, bequite large, as depicted in FIG. 4. The laminar flow region ischaracterized by smooth flow that is free from eddies. The turbulentflow region is characterized by a thicker boundary layer that has alarge number of eddies that act to transfer momentum from the fastermoving outer portions to the relatively slower portions nearer theairfoil surface. Thus, a turbulent boundary layer produces a greateramount of surface friction, than does a laminar boundary layer. Theincrease in surface friction causes increased aerodynamic drag thatrequires greater power consumption to maintain constant airfoil speed.

It should also be noted here that increases in drag will correspondinglycause an increase in the rate of heat transfer to the surface due to theincrease of surface friction (skin friction). In other words, anincrease in the skin friction coefficient will correspondingly increasethe convective heat transfer coefficient. Conversely, a decrease in skinfriction will decrease the rate of heat transfer to the surface.Accordingly, in accordance with an exemplary embodiment, it may bedesirable to modulate the skin friction in order to control the heattransfer characteristics of the fluid/surface interface.

A laminar boundary layer will, in many conditions, form at or near theleading edge of a conventional airfoil (for example) and extend rearwardtoward the points of minimum pressure on the upper and lower surfaces.According to Bernoulli's principle, the region between the leading edgeand the first minimum pressure point is one of a decreasing pressuregradient. Thereafter, the pressure gradient will increase and therelatively low kinetic energy of the air molecules closest to theairfoil surface may be insufficient to maintain laminar flow against thegradient. In this event it is possible that small perturbations in theboundary layer will develop into eddies that initiate a transition fromlaminar to turbulent flow. Alternatively, in the presence of higherpressure gradients, the molecules closest to the airfoil surface mayactually reverse their direction of motion and begin to move upstream,thereby causing the boundary layer to separate from the airfoil surface.This condition causes significantly more drag, and less lift, than aturbulent boundary layer, and reattachment will not normally occurunless some means is employed to reenergize the boundary layer. Thus, itis advantageous to control the boundary layer of an object in order toreduce aerodynamic drag and the energy losses associated therewith.

One such method of controlling the boundary layer is to providetraveling surface waves, surface displacements, and/or surfacedeformations which can be used to alter the transition from laminar toturbulent flow and/or prevent the onset of boundary layer separationnear the object. Altering the transition from laminar flow to turbulentflow in aerodynamic boundary layers on the surfaces of objects and/orpreventing boundary layer separation near the object is anotherimportant manner to reduce aerodynamic drag, and hence reduce energyconsumption for propelling the object. Alternatively, surface waves,deformations, and or displacements may be used to selectively increasedrag by inducing turbulent flow earlier and/or inducing boundary layerseparation.

As alluded to above, it may be desirable to increase drag on an object,for example if the object is a vehicle it may be desirable to increasedrag during vehicle braking. While some aircraft, for example, havemovable control surfaces that increase drag and lift, movable controlsurfaces on other vehicles such as automobiles or boats may not be aspractical. Increases in aerodynamic drag may also be used for steeringthe vehicle, for example by causing increased drag on one wing of anaircraft, the increase drag may cause the aircraft to turn due todifferential aerodynamic forces on different portions of the aircraftbody.

Another fluid flow state around an object, that may be desirable tocontrol by providing surface waves, deformations, and/or displacementsis supercavitation. Supercavitation occurs when an object moving througha fluid reaches a certain speed. For example, for an object movingthrough water, supercavitation may occur when the object moves in excessof 100 knots. At this speed it is possible for a bubble of air to formaround the object, beginning at the nose of the object. The bubble canextend completely around the entire object and hence the object is nolonger moving through the water, rather the object is moving throughair. This results in a significantly reduced amount of friction or dragbecause of the reduced density of the fluid. Hence, by inducing motionson the object surface it may be possible to induce the onset ofsupercavitation at lower speeds of the object itself.

Aircraft, other vehicles and any of a variety of objects moving througha fluid may often experience crosswinds that are tangential winds thathave various lift and drag effects. In other words, the relative windbeing experienced by an object is not typically directed parallel to thevelocity vector of the object. These so called crosswinds may results indifficulty in controlling the flight of an aircraft, for example, and inproviding a comfortable environment for aircraft passengers. Further,many solutions to decreasing drag do not contemplate crosswinds butrather have been designed using the assumption that the relative windvector is parallel to the velocity vector of the object. Thus, byproviding complex surface waves, deformations, and/or displacements,which may propagate in directions which are not necessarily parallel orperpendicular to the velocity vector of the object, it may be possibleto counteract the crosswind effect, or use the crosswinds advantageouslyto selectively decrease drag, and/or to selectively increase drag.

Yet another flow state that may affect one or more objects movingrelative to a fluid is the creation of a slipstream. A slipstream is theturbulent flow of air or water driven backwards for example bypropellers of a craft. A slipstream may also be the area of reducedpressure or forward suction produced immediately behind a fast movingobject as it moves through the air or water, for example an aircraft.There are a number of ways to affect the slipstream boundary layer orlaminar airflow layer either in front or behind the vehicle in order todecrease the turbulence or flow. For example, if three vehicles aretraveling together in a slipstream, with one following another one, allthree vehicles will travel faster. Thus, it may be desirable to improvethe slipstream effect and further to facilitate a vehicle traveling inthe slipstream. For example, it may be desirable to improve theslipstream characteristics of a bicycle rider on a racing team. Incertain situations a cyclist may wish to have a teammate use theslipstream advantageously so that the teammate does not have to use asmuch energy to follow the lead cyclist. In other situations, a leadcyclist may wish to disrupt the slipstream so that a cyclist fromanother team may not use the slipstream created by the lead cyclist totheir advantage. Scenarios such as this may be envisioned in a varietyof sports, such as but not limited to car racing, boat racing, aircraftracing, speed skating, etc. For the cyclist, it may be advantageous tocause traveling waves or other surface deformations on the surface ofthe cyclist's clothing and/or bicycle, in order to advantageously affectthe characteristics of the slipstream.

In a more critical application, it has long been known that a turbulentslipstream may cause difficulties for one aircraft following another,causing stalling or other undesirable situations. This is particularlytrue at airport locations in which multiple aircraft are put in queue asthey approach the runway for landing. The FAA has long had certainminimum following distances for different types of aircraft because ofthe magnitude and problems associated with the slipstream. Thus, byproviding traveling waves and/or other surface deformations on theaircraft, the slipstream may be advantageously affected which may inturn allow for a decrease in the minimum aircraft separation distanceand in turn lead to increases in airport efficiency.

Referring now to FIG. 5, a generalized system 500 for altering the dragon an object is depicted. System 500 is depicted with an object 510having a surface 515 with one or more actuators 520 and one or moresensors 525 associated therewith and distributed about surface 515. Inan exemplary embodiment, actuators 520 and sensors 525 may bedistributed on surface 515, within the material of surface 515, and/orunder surface 515. Further sensors 525 may be located at positions whichare not adjacent surface 515. Sensors 525 may be any of a variety ofsensors, including but not limited to one or more of pressure sensors,temperature sensors, turbulence sensors, strain sensors, accelerationsensors, location sensors, attitude sensors, vibration sensors, speedsensors, etc. Sensors 525 may measure various physical states of thebody and or states of the environment adjacent the body, for example,the physical states may include relative fluid velocity of the body,frequency of vibration of at least a portion of the body, amplitude ofvibration of at least a portion of the body, location of the body, fluidpressure of the fluid at least one location on the body, fluid pressureof the fluid at least one location adjacent the body, temperature atleast one location of the body, temperature of the fluid at least onelocation on the body, temperature of the fluid at least one locationadjacent the body, acceleration of at least one location of the body,etc. Sensors 525 provide a sensor signal to a signal filtering andsignal processing system 530. System 530 may include any of a variety offiltering devices including, but not limited to estimation algorithmsand circuits, filtering algorithms and circuits (low-pass, high-pass,band-pass, etc.), limiting circuits, etc. System 530 may also includeany of a variety of signal processing systems, including but not limitedto analog signal processor circuits, digital signal processing circuitsand algorithms, etc. A signal from signal filtering and signalprocessing system 530 is communicated to a processor 540. Processor 540may be any of a variety of processing devices including but not limitedto microprocessors, application specific integrated circuits (ASICs),field programmable gate arrays (FPGAs), etc. Processor 540 may use theconditioned sensor signals to generate an actuator signal by signalgenerator 550 to be communicated to actuators 520. Processor 540 mayimplement any of a variety or combination of applicable controlalgorithms, including but not limited to intelligent algorithms 560(artificial intelligence, fuzzy control, neural networks, geneticalgorithms, stochastic optimization based control, etc.), lookup tables570, traditional controllers 580 (classical controllers, multivariablecontrollers, optimal controllers, etc.), etc. Utilizing system 500, atraveling surface wave, a stationary surface wave, one or more dynamicsurface deformations, or one or more surface displacements may becreated on surface 515. In doing so, the air flow or other fluid flowover surface 515 may be affected to alter the drag on object 510 asdiscussed above.

For example, with reference to FIG. 6, a traveling surface wave 610 maybe created by actuators 620 associated with a surface 630 in thepresence of a fluid flow 640. As can be seen in reference to orthogonalaxes (X, Y, Z) 650 the wave may proceed in at least two orthogonaldirections (X,Y) and may displace the surface in a third direction (Z).Wave 610 may be a simple surface wave such as a sinusoidal wave or maybe any other type of wave, including but not limited to a superpositionof sinusoids. Further, waveform 610 may be aperiodic or damped, or maycomprise numerous surface displacements and/or deformations. Any of avariety of signal processing and analysis techniques may be applied inorder to generate the required waveforms, including but not limited toFourier transforms, fast Fourier transforms (FFTs), wavelet transforms,and the like. Because it is only in rare circumstances that the velocityvector of the relative wind would be only in the X direction, it may bedesirable to create traveling surface waves which travel in at least theX and Y directions. Also, because turbulence may be chaotic in nature,it may be desirable to have traveling surface waves that move in atleast the X and Y directions in an attempt to cancel at least some ofthe turbulence. Further, it may be desirable to have traveling surfacewaves which propagate in at least the X and Y directions in order tocontrol the directional forces on the body due to skin drag. This may beused for control and/or steering of the body.

Referring now to FIG. 7A, an actuatorable system 700 is depicted. System700 comprises an actuatorable surface 710 that can be deformed and/ordisplaced by an actuator 740 by movement of an actuator arm 730, that isassociated with surface 710 via an actuator connector 750. An exemplaryair volume element 720 above the actuator 740 moves if the surface isdeformed, as depicted in FIG. 7B. The deformation of surface 710, byextending a distance 760, is caused by extending actuator arm 730 fromactuator 740. Air volume element 720 may move perpendicular to thesurface or may have the effect of compressing the air above actuator740. Perpendicular movement may add perpendicular velocity 760 to thefluid flow. By making sequential deformations of this type across asurface, it may be possible to create a traveling wave across thesurface which induces increased flow velocity adjacent the surface. Bydoing so, skin friction drag may be controlled and potentially reduced.In an exemplary embodiment, the movement of the surface may help tochange the location of the onset of turbulence leading to an alterationin drag forces. In another exemplary embodiment, the surfacedeformations may create an apparent motion of the surface relative tothe fluid thereby altering the skin friction drag which is related torelative wind velocity. Further, surface deformations may provide energyto the fluid flow which aids the fluid's movement along the surfacethereby altering the skin friction drag.

Referring now to FIG. 8A, an actuatorable system 800 is depicted. Anactuatorable surface 810 may be deformed by an actuator 840. Air volumeelement 820 above actuator 840 moves if the surface is deformed. Inaccordance with the exemplary depiction in FIG. 8B, the deformation 830of the surface 810 is caused by extending the actuator arm 860. At leasta portion of air volume element 850 moves in a direction 870perpendicular to the deformed surface 830. In this particular example acomponent of the velocity of a portion of air element 850 is horizontalto the undeformed surface. A horizontal velocity in the direction of thefreestream may aid in reducing aerodynamic drag on the surface.

Referring now to FIGS. 9A-9E a flow manipulation system 900 inaccordance with at least one exemplary embodiment is depicted. FIG. 9Aillustrates a surface 950 in an unactuated state. FIG. 9B illustratessurface 950 in an actuated state in which surface 950 is deformed fromthe unactuated state. Surface 950 is deformed by one or more actuatorsforming a surface waveform, having a leading edge 910, a crest 920, atrough 930, and a trailing edge 940. The actuation is varied such thatthe waveform appears to travel at a velocity 960. Several waveforms 970,980, separated by unactuated surface 995, may move with apparentvelocities 990 and 960 respectively, moving air with, at a minimum, acomponent in the direction of the traveling waveform, thereby causing areduction in drag.

In accordance with an alternative embodiment, surface 950 may be viewedas contacting another surface. For example the underside of surface 950may be used to represent the bottom surface of a ski. As the undersideof the ski is deformed with the travelling wave(s) depicted, apropulsive for, or braking force may be derived. Producing suchpropulsive and/or braking forces provides the ski (and any body attachedto the ski) additional potential, for speed, braking ability, and/orcontrol. Generally, it may be seen that the concept of deforming asurface by multiple surface deformations and/or traveling surface wavesprovides additional control to not only surface drag applications inwhich a solid/fluid interface exists, but also may be applied insolid/solid interface applications and

Referring now to FIG. 10 an exemplary waveform embodiment 1000 isdepicted. A variation of actuation may result in waveform 1000, formingafter the unactuated surface 1010 and before unactuated surface 1020.The waveform 1000 includes a leading edge 1030; a trailing edge 1060; acrest 1040; a trough 1050; a crest amplitude 1092; and a troughamplitude 1094. The variation in actuation appears to move the waveformat a horizontal velocity 1070, moving a region of fluid 1090 a velocity1080.

Many various waveforms in accordance with exemplary embodiments may beformed by a variety of actuations and actuation sequences, for exampleFIG. 11 illustrates a sinusoidal waveform formed by actuation inaccordance with at least one exemplary embodiment. It may be desirableto form other complex waveforms, that are not strictly sinusoidal. Suchother waveforms may be formed from a superposition of sinusoidalwaveforms having varied amplitudes, frequencies, and phase shifts.

Referring now to FIG. 12 a flow manipulation system 1200 forming awaveform in accordance with at least one exemplary embodiment isdepicted. A surface 1210 may be deformed with respect to an unactuatedreference position 1220. For example actuator arms 1231, 1232, and 1233can respectively be extended away from a reference face 1250 of theactuators 1241, 1242, and 1243 forming a portion of the deformed surface1210. System 1200 depicts actuators having an extendable arm, such asbut not limited to hydraulic actuators, electromechanical actuators,inductive actuators, and the like. However, other types of actuators maybe equally applicable without departing from the scope of the claims.For example, the actuators may include but are not limited to microelectromechanical systems (MEMS) actuators, electroactive polymers,piezoelectric transducers, acoustic transducers, magnetic transducers,etc.

Referring now to FIG. 13, a flow manipulation system 1300 is depictedforming a waveform 1310 in accordance with at least one exemplaryembodiment. Waveform 1310, in this example, is created by pressuredifferences between opposing regions 1375 and 1395. The pressure issupplied by intake ports 1360 and 1370. The medium supplying thepressure travels through channels 1380 and 1390 into regions 1375 and1395 respectively. In the example shown the surface of a device has atleast two layers 1350 and 1340. A flexible first surface 1310, adjacentto the freestream 1377 is connected to another flexible second surface1330, by partition 1320. The region between partitions is referred to aschambers. The second surface 1330 is adjacent to a region 1397 lyingbetween the first 1350 and second 1340 layers. By varying the pressuresin neighboring chambers, deflections occur forming the shaped firstsurface 1310. By varying the pressures in a determined manner thewaveform can be moved creating a horizontal velocity component reducingthe drag.

Referring now to FIG. 14, various velocity profiles in a tube or channel1400 that can be formed by using various exemplary embodiments isdepicted. The tube or channel is formed by walls 1410 with a fluidregion 1420 between. FIG. 14 depicts a velocity profile “A” of aconventional flow in the tube with a maximum velocity 1430 in the centerof the tube with reference to reference line “I.” Using exemplaryembodiments, various profiles can be achieved reducing the drag or evenincreasing the fluid flow. For example if the waveforms (not shown) onthe inner surface of wall 1410 move downstream at a velocity less thanthe freestream velocity 1430, the cross-stream profile forms velocityprofile “B.” If the waveforms travel downstream at the same velocity asthe freestream velocity 1430, then the cross-stream profile formsvelocity profile “C.” If the waveforms travel faster 1440 downstreamthan the freestream velocity 1430 then the profile forms velocityprofile “D.”

Referring now to FIG. 15, at least one exemplary embodiment of a flowmanipulation system 1500 having sensors 1540, 1550, and 1560 (e.g.pressure sensors, temperature sensors, and other flow characteristicmeasuring sensors as known by one of ordinary skill) is depicted. FIG.15 depicts two velocity profiles G and H along a surface. The zerovelocity reference lines are R and S respectively. Line J represents thezero velocity line, which occurs at two positions in velocity profile H,one at the wall and the other 1530 away from the wall, a characteristicof flow separation. The separation point 1580, is the point along thesurface where the zero velocity line J leaves the surface. Separationincreases drag, which can be reduced by flow manipulation via actuators1570, which can be used to add velocity parallel to the surface alteringthe separation point. The actuators can be controlled by amicroprocessor 1590, which can receive data from the sensors 1540, 1550,and 1560 via data lines 1595.

Referring now to FIG. 16, an exemplary embodiment of an active skinsystem 1600 is depicted. Active skin system 1600 comprises a first layercomprising a ferric material layer 1610. Ferric material layer 1610 isconfigured to be flexible and may be a continuous or semi-continuouslayer of ferric paint, or may comprise ferric elements or further maycomprise any layer having magnetic or magnetically attractive material.An elastic layer may be disposed below ferric material layer 1610, whichmay comprise an array of springs, or may comprise an elastic materialhaving some spring constant, or may be some other configurationproducing an elastic layer. A solenoid layer 1630 is disposed belowelastic layer 1620. Solenoid layer 1630 may comprise an array of deviceshaving a mechanism to produce a magnetic field. In one embodiment,solenoid layer 1630 comprises an array of solenoids 1632. Layers 1610,1620, and 1630 are configured in such a way that changing parameters inthe layer 1630 causes a deflection in layer 1610. For example, in theexemplary embodiment depicted where layer 1630 comprises an array ofsolenoids 1635 and layer 1610 comprises ferric paint, applying a voltageacross one of the solenoids produces a magnetic field that will deflectthe first layer in a direction depending on the direction of themagnetic field produced by the solenoid.

In order to control the layers 1610, 1620, and 1630, with an acousticwave, a piezoelectric layer 1640 may be added. Piezoelectric layer 1640comprises piezoelectric materials and is configured such that anacoustic wave can propagate in the layer. The acoustic wave causes adeflection in piezoelectric layer 1640 as it propagates through thelayer, causing a deformation of the piezoelectric material, which inturn causes a voltage difference across the layer. This voltage isapplied to the solenoid, and creates the deflection in the active skinas described above.

Referring now to FIG. 17, another exemplary embodiment of an active skinsystem 1700 is depicted. System 1700 comprises flexible membrane layer1710 that is configured to be flexible. A response layer 1720 comprisesa material that changes shape in response to an applied voltage and/ortemperature, such as a piezoelectric material or nitinol (NickelTitanium Naval Ordnance Laboratory) material which is a family ofintermetallic materials, which contain a nearly equal mixture of nickel(55 wt. %) and titanium, or other shape memory materials. Apiezoelectric layer 1730 comprises piezoelectric materials and isconfigured such that an acoustic wave can propagate in the layer. Apropagating acoustic wave causes a deflection in the fourth layer as itpropagates down the layer, causing a deformation of the piezoelectricmaterial, which causes a voltage difference across the layer. Thisvoltage is applied to the solenoid, and creates the deflection in theactive skin system 1700 as described above.

Referring now to FIG. 18, a method 1800 of altering fluid flow about abody moving relative to a fluid is depicted. Method 1800 comprisesproviding a body in a fluid flow (process 1810). Such a body may includeany type of surface exposed to a fluid moving relative to the surface,whether it be a vehicle surface, etc. Alternatively, the surface may bea surface which contacts another surface rather than a surface exposedto a fluid flow. The surface generally extends in at least a firstdirection and a second direction where the first direction is defined asorthogonal to the second direction. A system associated with the surfaceor with the fluid flow determines a need for surface deformations(process 1820). Such a system may be a control system, a sensor system,a man-machine interface system, an artificial intelligence system, etc.The need for deformations may be any of a variety of requirements, suchas but not limited to reducing drag, changing the aerodynamiccharacteristics of the surface or of the body, controlling movement ofthe body relative to the fluid, etc. Once the need for deformations hasbeen determined, a signal is developed which may be used to create thesurface deformations (process 1830). Such a signal may be but is notlimited to an electrical signal, an optical signal, a radio signal, anacoustic signal, and the like. The signal is then applied to one or moreactuators to generate the surface deformations (process 1840). Inaccordance with an exemplary embodiment the deformations generated maybe a series of deformations which move in both the first and seconddirections. The series of deformations may be in the form of a surfacewave. Such a surface wave may be a simple sinusoidal wave, or any othertype of wave formed from a superposition of more than one wave.

Referring now to FIG. 19, a method 1900 of altering fluid flow about asurface is depicted. Method 1900 includes providing a surface that isdefined by more than one orthogonal direction in the presence of a fluidflow (process 1910). In association with the surface, actuators areprovided that are capable of deforming the surface (process 1920). Suchactuators may be but are not limited to any of a variety of actuatorsincluding electromechanical, hydraulic, MEMS, electroactive polymer, andthe like. At least one characteristic of the fluid flow based on asignal from at least one sensor is detected (process 1930). Fluid flowcharacteristics may be any of a variety of characteristics whichrelating to the physical state of the fluid flow about the body or ofthe fluid flow affecting the state of the body. The signal from thesensor is communicated to a processor (process 1940). The processor isconfigured to run an algorithm for controlling the at least one actuatorbased on the signal to create a surface wave that moves with a velocityhaving components of both the first and second directions (process1950).

Referring now to FIG. 20, an exemplary embodiment of a device 2000 forcreating a selectively variable frequency sound is depicted. The device2000 may be but is not limited to a musical instrument or other soundgenerating device. Device 2000 comprises an passageway 2010 throughwhich a fluid 2030, such as but not limited to air, is directed to flow.A selectively deformable surface 2040 comprises at least a portion ofthe airway. An actuator system 2020 is configured to deform surface 2020in response to an input. The input may be computer controlled, usercontrolled, etc. The deformation to surface 2040 by actuators 2020 causea change in fluid flow 2030 and thereby causing a change in the soundfrequency generated by device 2000.

In accordance with another exemplary embodiment applications may be madeof active skin components for internal combustion engines. For example,internal combustion engines are typically used to generate vehiclethrust. One particular component of efficient combustion of an air/fuelmixture in an internal combustion engine is atomization of the fuel withthe air. Since the fuel is mixed with the air at a time very close tothe time of combustion, it is important that the atomization processoccur quickly. Furthermore, turbulent airflows prior to combustion candisadvantageously cause the fuel to separate from the air. Thus, bycontrolling the turbulence characteristics of the fuel and/or air supplyand atomization system, rapid atomization of fuel when mixed with theair that deters the fuel from separating from the air under turbulentconditions may be accomplished.

In accordance with another exemplary embodiment, applications may bemade of active skin components for vehicle tires. For example, vehicletires are conventionally used for vehicle thrust. The traction of thetire facilitates acceleration, braking and turning. Improved tractionmay be generated by greater contact area between the road surface andthe tire surface. Improved traction may be desirable for vehicle brakingand control. Alternatively, less traction may be generated by providingless contact area between the road surface and the tire surface.Decreased traction may be desirable during travel at high speeds inorder to improve fuel efficiency. Therefore, by applying an activesurface on the surface of a tire, the contact area of the tire may beselectively controlled in order to gain the desired performance.

In accordance with yet another exemplary embodiment, applications ofactive surface components may include improving pipe flowcharacteristics. Such control of active surfaces in pipes may be carriedout using microfluidics, MEMS, etc. Such applications may includeapplications where a fluid is pumped through the pipe, drillingapplications, medical applications, etc. In such an instance the insidesurface may be controlled in order to alter the flow characteristics.

In yet another exemplary embodiment, water vessels (boats), airplanes,or other vehicles may benefit from an active skin. By controlling theactive skin, fluid flow may be affected thereby controlling drag. Bycontrolling drag, fuel efficiency may be improved, or control of thevehicle motions may also be controlled.

In yet still another exemplary embodiment, the active skin techniquesdescribed may be applied to clothing, for example for swimmers,cyclists, and other athletes, thereby producing better dragcharacteristics.

In still yet another exemplary application an active skin may be appliedto snow skis or other skis in which you can increase and/or decreasedrag to increase or decrease traction as desired.

Yet further exemplary applications are in the field of artillery, forexample to decrease friction between the barrel and the projectile orthe air and the projectile or on the sides of the projectile as it movesthrough the target. For example, a bullet equipped withmicroelectromechanical actuators to generate surface waves could besteered in mid-air.

Yet still another application may be a pump made of many small tubes tokeep reynolds number low. In a laminar flow machine or pump, skin dragmay predominate. Thus, flow characteristics through the tubes may beimproved by providing traveling waves down the small tubes to decreasedrag or to increase the fluid flow. Fluid will be slow at the pointwhere it enters system and then accelerate down the length of the tubes,so the wave would have to similarly accelerate down the length of thetubes to keep the same relative wave.

Yet still in accordance with another exemplary embodiment, the travelingwave may, instead of matching the velocity of the fluid, have a velocitygreater than that of the fluid. This would create a situation wherebythe wave on the surface of the body would have excess acceleration tomove the fluid out of the way. Further, if the traveling wave has vectorand time components, the wave can be steered. In yet another embodiment,waves in the opposite direction from the previous viewpoint may becreated to actively create traction or to pump fluids.

When implementing the active skin as described above, many methods todevelop the desired fluid flow characteristics may be used. One suchmethod is to generate the amplitude and the wavelength based on avariety of factors, one of which may be sensor output. In such aninstance it may be desirable to form the peak amplitude of the wavehaving at least a mean-free path in the fluid flowing over the surfaceof the solid body to provide effective coupling between the fluid andthe solid body. Practically, the amplitude may be many mean-free paths.Another consideration is the wavelength of the traveling wave, which maybe a large multiple of the mean-free path.

In a general sense, those skilled in the art will recognize that thevarious embodiments described herein can be implemented, individuallyand/or collectively, by various types of electro-mechanical systemshaving a wide range of electrical components such as hardware, software,firmware, or virtually any combination thereof, and a wide range ofcomponents that may impart mechanical force or motion such as rigidbodies, spring or torsional bodies, hydraulics, and electro-magneticallyactuated devices, or virtually any combination thereof. Consequently, asused herein “electro-mechanical system” includes, but is not limited to,electrical circuitry operably coupled with a transducer (e.g., anactuator, a motor, a piezoelectric crystal, etc.), electrical circuitryhaving at least one discrete electrical circuit, electrical circuitryhaving at least one integrated circuit, electrical circuitry having atleast one application specific integrated circuit, electrical circuitryforming a general purpose computing device configured by a computerprogram (e.g., a general purpose computer configured by a computerprogram which at least partially carries out processes and/or devicesdescribed herein, or a microprocessor configured by a computer programwhich at least partially carries out processes and/or devices describedherein), electrical circuitry forming a memory device (e.g., forms ofrandom access memory), electrical circuitry forming a communicationsdevice (e.g., a modem, communications switch, or optical-electricalequipment), and any non-electrical analog thereto, such as optical orother analogs. Those skilled in the art will also appreciate thatexamples of electro-mechanical systems include but are not limited to avariety of consumer electronics systems, as well as other systems suchas motorized transport systems, factory automation systems, securitysystems, and communication/computing systems. Those skilled in the artwill recognize that electro-mechanical as used herein is not necessarilylimited to a system that has both electrical and mechanical actuationexcept as context may dictate otherwise.

In a general sense, those skilled in the art will recognize that thevarious aspects described herein which can be implemented, individuallyand/or collectively, by a wide range of hardware, software, firmware, orany combination thereof can be viewed as being composed of various typesof “electrical circuitry.” Consequently, as used herein “electricalcircuitry” includes, but is not limited to, electrical circuitry havingat least one discrete electrical circuit, electrical circuitry having atleast one integrated circuit, electrical circuitry having at least oneapplication specific integrated circuit, electrical circuitry forming ageneral purpose computing device configured by a computer program (e.g.,a general purpose computer configured by a computer program which atleast partially carries out processes and/or devices described herein,or a microprocessor configured by a computer program which at leastpartially carries out processes and/or devices described herein),electrical circuitry forming a memory device (e.g., forms of randomaccess memory), and/or electrical circuitry forming a communicationsdevice (e.g., a modem, communications switch, or optical-electricalequipment). Those having skill in the art will recognize that thesubject matter described herein may be implemented in an analog ordigital fashion or some combination thereof.

Those skilled in the art will recognize that it is common within the artto implement devices and/or processes and/or systems in the fashion(s)set forth herein, and thereafter use engineering and/or businesspractices to integrate such implemented devices and/or processes and/orsystems into more comprehensive devices and/or processes and/or systems.That is, at least a portion of the devices and/or processes and/orsystems described herein can be integrated into other devices and/orprocesses and/or systems via a reasonable amount of experimentation.Those having skill in the art will recognize that examples of such otherdevices and/or processes and/or systems might include—as appropriate tocontext and application—all or part of devices and/or processes and/orsystems of (a) an air conveyance (e.g., an airplane, rocket, hovercraft,helicopter, etc.), (b) a ground conveyance (e.g., a car, truck,locomotive, tank, armored personnel carrier, etc.), (c) a building(e.g., a home, warehouse, office, etc.), (d) an appliance (e.g., arefrigerator, a washing machine, a dryer, etc.), (e) a communicationssystem (e.g., a networked system, a telephone system, a Voice over IPsystem, etc.), (f) a business entity (e.g., an Internet Service Provider(ISP) entity such as Comcast Cable, Quest, Southwestern Bell, etc), or(g) a wired/wireless services entity such as Sprint, Cingular, Nextel,etc.), etc.

One skilled in the art will recognize that the herein describedcomponents (e.g., steps), devices, and objects and the discussionaccompanying them are used as examples for the sake of conceptualclarity and that various configuration modifications are within theskill of those in the art. Consequently, as used herein, the specificexemplars set forth and the accompanying discussion are intended to berepresentative of their more general classes. In general, use of anyspecific exemplar herein is also intended to be representative of itsclass, and the non-inclusion of such specific components (e.g., steps),devices, and objects herein should not be taken as indicating thatlimitation is desired.

With respect to the use of substantially any plural and/or singularterms herein, those having skill in the art can translate from theplural to the singular and/or from the singular to the plural as isappropriate to the context and/or application. The varioussingular/plural permutations are not expressly set forth herein for sakeof clarity.

The herein described subject matter sometimes illustrates differentcomponents contained within, or connected with, different othercomponents. It is to be understood that such depicted architectures aremerely exemplary, and that in fact many other architectures can beimplemented which achieve the same functionality. In a conceptual sense,any arrangement of components to achieve the same functionality iseffectively “associated” such that the desired functionality isachieved. Hence, any two components herein combined to achieve aparticular functionality can be seen as “associated with” each othersuch that the desired functionality is achieved, irrespective ofarchitectures or intermedial components. Likewise, any two components soassociated can also be viewed as being “operably connected”, or“operably coupled”, to each other to achieve the desired functionality,and any two components capable of being so associated can also be viewedas being “operably couplable”, to each other to achieve the desiredfunctionality. Specific examples of operably couplable include but arenot limited to physically mateable and/or physically interactingcomponents and/or wirelessly interactable and/or wirelessly interactingcomponents and/or logically interacting and/or logically interactablecomponents.

While particular aspects of the present subject matter described hereinhave been shown and described, it will be apparent to those skilled inthe art that, based upon the teachings herein, changes and modificationsmay be made without departing from the subject matter described hereinand its broader aspects and, therefore, the appended claims are toencompass within their scope all such changes and modifications as arewithin the true spirit and scope of the subject matter described herein.Furthermore, it is to be understood that the invention is defined by theappended claims. It will be understood by those within the art that, ingeneral, terms used herein, and especially in the appended claims (e.g.,bodies of the appended claims) are generally intended as “open” terms(e.g., the term “including” should be interpreted as “including but notlimited to,” the term “having” should be interpreted as “having atleast,” the term “includes” should be interpreted as “includes but isnot limited to,” etc.). It will be further understood by those withinthe art that if a specific number of an introduced claim recitation isintended, such an intent will be explicitly recited in the claim, and inthe absence of such recitation no such intent is present. For example,as an aid to understanding, the following appended claims may containusage of the introductory phrases “at least one” and “one or more” tointroduce claim recitations. However, the use of such phrases should notbe construed to imply that the introduction of a claim recitation by theindefinite articles “a” or “an” limits any particular claim containingsuch introduced claim recitation to inventions containing only one suchrecitation, even when the same claim includes the introductory phrases“one or more” or “at least one” and indefinite articles such as “a” or“an” (e.g., “a” and/or “an” should typically be interpreted to mean “atleast one” or “one or more”); the same holds true for the use ofdefinite articles used to introduce claim recitations. In addition, evenif a specific number of an introduced claim recitation is explicitlyrecited, those skilled in the art will recognize that such recitationshould typically be interpreted to mean at least the recited number(e.g., the bare recitation of “two recitations,” without othermodifiers, typically means at least two recitations, or two or morerecitations). Furthermore, in those instances where a conventionanalogous to “at least one of A, B, and C, etc.” is used, in generalsuch a construction is intended in the sense one having skill in the artwould understand the convention (e.g., “a system having at least one ofA, B, and C” would include but not be limited to systems that have Aalone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together, etc.). In those instances where aconvention analogous to “at least one of A, B, or C, etc.” is used, ingeneral such a construction is intended in the sense one having skill inthe art would understand the convention (e.g., “a system having at leastone of A, B, or C” would include but not be limited to systems that haveA alone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together, etc.). It will be furtherunderstood by those within the art that virtually any disjunctive wordand/or phrase presenting two or more alternative terms, whether in thedescription, claims, or drawings, should be understood to contemplatethe possibilities of including one of the terms, either of the terms, orboth terms. For example, the phrase “A or B” will be understood toinclude the possibilities of “A” or “B” or “A and B.”

While various aspects and embodiments have been disclosed herein, otheraspects and embodiments will be apparent to those skilled in the art.The various aspects and embodiments disclosed herein are for purposes ofillustration and are not intended to be limiting, with the true scopeand spirit being indicated by the following claims.

1. A method of altering fluid flow about a body moving relative to afluid, comprising: providing a body having a first surface, the firstsurface actuated by a first set of one or more actuators; exposing thefirst surface of the body to the fluid, the first surface extending inat least a first direction and a second direction, the first directionbeing orthogonal to the second direction, the second direction beingsubstantially orthogonal to the direction of fluid flow, and the seconddirection being parallel to the surface; generating more than onedeformation of the first surface of the body using the first set of oneor more actuators, wherein the more than one deformation includes aseries of variations propagating in a direction tangential to thesurface and at a non-zero angle with the direction of fluid flowrelative to the body; and generating more than one deformation of thefirst surface of the body using the first set of one or more actuators,wherein the more than one deformation includes a series of variationspropagating in a direction tangential to the surface and along thedirection of fluid flow relative to the body.
 2. The method of claim 1,wherein the variations comprise a surface wave.
 3. The method of claim1, wherein generating the more than one deformation comprises: inducingthe series of variations to form a surface wave that comprises asuperposition of more than one surface wave.
 4. The method of claim 1,further comprising: sensing a physical state of the body.
 5. The methodof claim 4, wherein the physical state of the body comprises at leastone of relative fluid velocity of the body, frequency of vibration of atleast a portion of the body, amplitude of vibration of at least aportion of the body, location of the body, fluid pressure of the fluidat least one location on the body, fluid pressure of the fluid at leastone location adjacent the body, temperature at least one location of thebody, temperature of the fluid at least one location on the body,temperature of the fluid at least one location adjacent the body,rotational acceleration of the body, orientation of the body, rotationalrate of the body, stress at least one location of the body, strain atleast one location of the body, fluid density, shear force, location ofturbulent flow relative to the body, the thickness of a laminar flowboundary layer adjacent the first surface, or acceleration of at leastone location of the body.
 6. The method of claim 1, further comprising:determining the location of turbulent fluid relative to the body.
 7. Themethod of claim 6, further comprising: generating a signal that is usedto generate the more than one deformation of the first surface based onthe location of the turbulent fluid relative to the body.
 8. The methodof claim 1, further comprising: determining the thickness of a laminarflow boundary layer adjacent the first surface.
 9. The method of claim8, further comprising: generating a signal that is used to generate themore than one deformation of the first surface based on the thickness ofthe laminar flow boundary layer adjacent the first surface.
 10. Themethod of claim 1, further comprising: sensing a physical state of thebody; communicating the physical state of the body to a processor; andapplying a control algorithm to produce a command signal for generatingthe more than one deformation based on the physical state of the body.11. The method of claim 10, wherein the control algorithm comprises atleast one of a classical control algorithm, an adaptive controlalgorithm, a nonlinear control algorithm, an intelligent controlalgorithm, a multivariable control algorithm, a neural controlalgorithm, a digital control algorithm, an analog control algorithm, aparametric control algorithm, a table look-up algorithm, or a fuzzycontrol algorithm.
 12. The method of claim 1, further comprising:sensing a physical state of the body or the fluid flow; communicatingthe physical state of the body or the fluid flow to a processor; andapplying an estimation algorithm, the estimation algorithm determiningat least one estimated parameter, the at least one estimated parameterused in a process to produce a command signal for generating the morethan one deformation.
 13. A method of altering fluid flow about asurface, the surface being defined by at least a first direction and asecond direction orthogonal to the first direction, the fluid flowdirection having a projection parallel to the first direction andorthogonal to the second direction and the first and second directionsbeing tangentially parallel to the surface, comprising: providing asurface configurable with one or more actuators for deforming thesurface; coupling to the surface at least one actuator capable ofdeforming the surface; detecting at least one physical state based on asignal from at least one sensor; and responsive to the detecting atleast one physical state, controlling the at least one actuator based onthe signal to create deformations which propagate with a velocity havingcomponents of both the first and second directions.
 14. The method ofclaim 13, wherein the deformation comprises a surface wave.
 15. Themethod of claim 13, wherein controlling the at least one actuatorcomprises: inducing the deformations to form a surface wave thatcomprises a superposition of more than one surface wave.
 16. The methodof claim 13, wherein the physical state comprises at least one ofrelative fluid velocity of the body, frequency of vibration of at leasta portion of the body, amplitude of vibration of at least a portion ofthe body, location of the body, fluid pressure of the fluid at least onelocation on the body, fluid pressure of the fluid at least one locationadjacent the body, temperature at least one location of the body,temperature of the fluid at least one location on the body, temperatureof the fluid at least one location adjacent the body, and accelerationof at least one location of the body.
 17. The method of claim 13,further comprising: determining the location of turbulent fluid relativeto the body.
 18. The method of claim 17, further comprising: generatinga signal that is used to generate the more than one deformation of thesurface based on the location of the turbulent fluid relative to thebody.
 19. The method of claim 13, further comprising: determining theapproximate thickness of a laminar flow boundary layer adjacent thesurface.
 20. The method of claim 19, further comprising: generating asignal that is used to generate the more than one deformation of thesurface based on the thickness of the laminar flow boundary layeradjacent the surface.
 21. The method of claim 13, wherein thecontrolling comprises applying at least one of a classical controlalgorithm, an adaptive control algorithm, a nonlinear control algorithm,an intelligent control algorithm, a multivariable control algorithm, aneural control algorithm, a digital control algorithm, an analog controlalgorithm, a parametric control algorithm, a table look-up algorithm,and a fuzzy control algorithm.
 22. The method of claim 13, furthercomprising: sensing a physical state of the body or the fluid flow;communicating the physical state of the body or the fluid flow to atleast one of a processor or a storage element; and applying anestimation algorithm, the estimation algorithm determining at least oneestimated parameter, the at least one estimated parameter used in aprocess to produce a command signal for generating the more than onedeformation.